In order to determine the forces in the highlighted members (bars GEDC are parallel to HAB), we must first consider the direction of each force. Bars GEDC will have a tension force due to compression between two other bars, while HAB will have a compression force due to tension from two other bars. This can be seen using vector diagrams, which can help visualize and analyze such relationships within our structure.
1) Determine the forces in the highlighted members (bars GEDC are parallel to HAB)
We will start by looking at bar GEDC, which has an external load applied on it. This produces a downward force (F1) on bar GEDC along its length, while simultaneously creating an upward reaction force (R1) on both Bar A and Bar B where they intersect with Bar G EDC. These forces are equal in magnitude but opposite in direction since they balance out each other’s forces; this is known as Newton’s third law of motion (McGill University 2020). In addition, there is also an internal couple moment M2 that acts along the length of bar G EDC due to the different lengths of Bars A and B.
Next we look at bar HAB which also has an external load applied onto it producing a downward force F2 along its length . This subsequently creates upward reaction forces R2 on both Bar C and Bar D where they intersect with Bar H AB . Just like before ,these two reaction forces are equal in magnitude but opposite direction thus fulfilling principles outlined by Newton’s Third Law . Moreover ,there internal couple moment M2 acting along length this particular section due difference distances between points contact.
References
- McGill University What Is Newton\’s Third Law Of Motion? [Internet]. US National Library Of Medicine ;2020 Apr 1[cited 2021 May 18] Available From : https://wwwpubmedcentralnihgov / articlerenderfcgitool=pmcentrez&artid = 8173109